LWG3315 Correct Allocator Default Behavior

Also fixes NB US 162, US 163 (C++20 CD).

Author: Dawn Perchik

source/lib-intro.tex

@@ -2200,12 +2200,12 @@
   (not used)                &
   \effects Constructs an object of type \tcode{C} at
     \tcode{c}               &
-  \tcode{::new ((void*)c) C(forward<\brk{}Args>\brk(args)...)}  \\ \rowsep
+  \tcode{construct_at(c,~std::\brk{}forward<Args>\brk{}(args)...)}  \\ \rowsep
 
 \tcode{a.destroy(c)}        &
   (not used)                &
   \effects Destroys the object at \tcode{c}  &
-  \tcode{c->\~{}C()}           \\  \rowsep
+  \tcode{destroy_at(c)}     \\  \rowsep
 
 \tcode{a.select_on_container_copy_construction()} &
   \tcode{X}                 &